Ratio of observational (Ṁ_lit) and predicted (Ṁ) mass-loss rates as a function of effective temperature T_eff for B supergiants. Only observational mass-loss rates that are either independent of clumping or were corrected for clumping in some way are plotted. The observational results are based on X-ray line profiles (Puebla et al. 2016), UV spectrum analysis with clumping (Hainich et al. 2020), and wind bow shocks (Kobulnicky et al. 2019). The gray lines denote predictions of Petrov et al. (2016) for different luminosities and masses and the gray squares correspond to predictions of Björklund et al. (2020) and T_eff = 27 500 K.